Hotness isn’t the only thing that makes people attractive. It can be charisma or charm or grace or talent or wittiness - but regardless of what specific quality it is, if you’re a celebrity you’ve got something. It’s literally part of the job description - you become a celebrity because people are willing to pay to watch you.
There have been a few cases where a celebrity met and married a “normal person”: Matt Damon, Robert DeNiro, Marlee Matlin, Julia Roberts, David Schwimmer.
Maybe “normal person” isn’t the best term. How about “somebody outside show business”?
If a “hot” male celebrity marries an equally “hot” female celebrity, I always suspect it’s because she’s a ‘beard’ covering for him and they have an 'arrangement. Or it’s for mututal publicity for both of them. Hotness is no indication of a quality person, hotness does not guarantee love. If they look good together, the fans go 'awww…they are so cute!!!" and pair up, than the actor, who is a 5, and the actress, who is also a 5, together now equal a 10 on the publicity scale.
I know this because I’m told so by many show biz and celebrity gossip sites! 
Though if any of that were true..how does that work? How could you marry just for publicity? What can your lives possibly be like? If true, celebrities really are a breed apart.
Marriage as a partnership to protect and promote mutual business interests has been a tried and tested practice for centuries; heck, it was the expected standard for royalty, landed gentry and upper bourgeoisie until the 20th century.
And even in the cases where a celeb has married a normal person, it’s going ti be very rare that the man in the pair is not the celeb or at least filthy rich. Marlee Matlin marrying a policeman is a rare case.
This is an example of why it’s so difficult to find a relationship that is celebrity/non-celebrity.
By virtue of the fact that he was a Mr. Liz Taylor, Larry Fortensky is now a “celebrity.”
Jeff Daniels is married to a woman not in the business. And spends most of his time in Michigan. Is he considered a celebrity, though?
I can’t think of an example right now but I think there have been several female celebs that were married to very successful doctors or surgeons. Wasn’t Mary Tyler Moore married to a famous cardiologist? Maybe I’m thinking of someone else.
Ingrid Bergman was married to Peter Lindstrom a neurosurgeon. She later left him for Roberto Rosseilini a Director. A few years ago some wannabe feminist on a show gave that as an example of a successful woman leaving her worthless husband for someone more suited, Lindstrom ironically made several pioneering advances in brain surgery, so I think his worthlessness is overstated.
Within the industry, I understand, such persons are known as “civilians”.
Right: *showbiz *“celebrities” – and that’s what is being meant here, isn’t it, I don’t see anyone talking about star lawyers/CEOs/novelists-- will often meet and date people not in showbiz, but who will be socializing in similar circles by virtue of being highly succesful in their field. Is that dating “regular folks”? Or is it dating fellow members of the elite who just happen to be elite in a less-visible trade?
OTOH you have the Taylor/Fortensky type of case, and that again involves the element of moving in circles of common interests: They meet at Betty Ford Clinic. Were it not for a shared propensity for chemical dependency and a shared interest in getting the best-rated treatment for it, it would not have happened just casually.
Kathy Ireland is married to an orthopedic surgeon.
Surgeons tend to be wealthy. Wealthy men can pair with celebrities. Women marry up.
Actually, I think that the brevity of so many celebrity relationships is because they are like the rest of us, in some very important ways. It’s easy for an ordinary guy to look at some hot starlet and thing “Man, I’d love to be married to her”. But we’re not basing that on personality, or interests, or any of the things that are really important in a marriage, but just on superficial things like looks. And so it’s just as well that we don’t have a chance with them, because if, say, I were to marry Scarlett Johansson, or Keira Knightly, it almost certainly wouldn’t work out. Well, a hot male celebrity will think that those ladies are just as attractive as any of the rest of us would, and will have the same “I’d love to be married to her” reaction that a normal guy would have, except that in his case, he does have a chance. And so celebrities go ahead and form relationships with celebrities, just like most of us think we want to, and the relationships fail, just like they would with most of us.
Meryl Streep.
Don Gummer is a successful sculptor. He’s still in the creative business.
He isn’t a celebrity by any reasonable definition of the term.
He’s in the same social class, the same class of creative types. One of the world’s premier sculptors isn’t a regular guy. He’s not a beat cop like Marlee Matlin’s husband. Celebrities generally match up with celebrities, rich people, powerful people, generally highly successful people in whatever field, or fellow creative industry people.
I believe the OP mostly “reads” about those dates who are “already celebrities on their own” due to media sampling bias – a fling between hit singer/actress Callypigia Hottie and NBA player Stud Makeitrain, will get far more publicity than if she’s hanging out with award-winning writer Remington Olivetti because the former has fans and press following his personal life, as well.
I find your ideas intriguing and wish to subscribe to your gossip column. 